The goal of this project is to identify a mouse model for the human disease Meckel syndrome. The use of random chemical mutagenesis in the Meckel syndrome candidate region has produced several mouse mutants that have phenotypes similar to human patients. These mutant mice will be further characterized as models for Meckel syndrome. The mutations will then be mapped, and the mutated genes will be identified by positional cloning. The causative gene for Meckel syndrome has not yet been isolated from studies in human patients, although two candidate regions have been identified through linkage analysis on affected families. Therefore, this project seeks to identify the Meckel syndrome gene, which will be useful as a diagnostic tool for families with a history of Meckel syndrome. Additionally, the mouse model will be used to characterize the biological pathway that is affected in Meckel syndrome which would otherwise be difficult due to the rarity and severity of the disease in humans.